This invention relates generally to the art of film wrapping systems for use in wrapping objects with shrink wrap film and, more particularly, to improvements directed to preparing the film wrapping system for wrapping products of differing dimensions.
A wide variety of systems are known for wrapping packages in thermoplastic film. Some of these machines are known as L-sealers because they form “trim seals” utilizing a web of center folded film. More recent machines utilize a continuous longitudinal sealer and a cross sealer which moves at approximately the velocity of the packages as they travel through the machine so that the packages are not stopped while the machine performs the end sealing operation. One example of a shrink wrap packaging system is disclosed in U.S. patent application Ser. No. 10/286,523, filed Nov. 1, 2002, assigned to the Assignee of this invention and hereby incorporated by reference in its entirety.
Most known shrink wrap packaging systems utilize film which is provided on a roll in two plies with each ply being joined together by a longitudinal fold line. The two-ply film is dispensed from a supply roll and delivered to a wrapping station of the shrink wrap packaging system. The film is commonly inverted and reoriented to provide an opening for convenient access and entry of the products between the dual plies of the film. The film is reoriented in many shrink wrap packaging systems by an upper and a lower film inverting rod or plow system. The upper and lower film inverting rods are positioned above and below, respectively, a feed conveyor which is advancing the products to be wrapped.
Shrink wrap packaging systems of these types process and wrap a variety of different products. Commonly, such products are of differing shapes, sizes and dimensions. For example, shrink wrap packaging systems may process and wrap a single compact disc (CD) package which is very thin and other consumer retail items which have a significantly greater height and a larger width dimension. One problem associated with many known shrink wrap packaging systems is the difficulty in efficiently processing and wrapping a wide variety of packages and products, especially those having distinctly different dimensions, heights and widths.
Recent advancements in the art of shrink wrap packaging systems have included adjustable film inverter rods in which a spacing between the rods is adjustable to accommodate a variety of differing height products being wrapped. The film inverter rods are only one of many pairs of components in typical film wrapping systems which must be adjusted depending upon the dimensions of the product being wrapped. Moreover, the spacing between the various pairs of associated components of the shrink wrap packaging systems is not always the same as the product dimension. For example, while the spacing between the film inverter rods is roughly equal to the height of the product being wrapped, the position of a side seal mechanism for joining the free edges of the shrink wrap film and enclosing the product is roughly half the height of the product. Generally, the side seal should be located approximately at the equator of the product and the side seal mechanism should be centered at that location above the platform or conveyor supporting the product.
Many other components of the shrink wrap packaging system likewise must be adjusted and appropriately positioned for a given product and associated product dimensions. In one shrink wrap packaging system commercially available from the assignee of this invention, five different height adjustments and three different width adjustments must be made to the system to properly set it up for wrapping a given product. An operator of a shrink wrap packaging system typically must initially measure the product and perform the required calculations to determine the spacing between each of the eight or so pairs of components required for proper wrapping of the product. The set up procedure for the shrink wrap packaging system requiring these operations can take anywhere from eight to 19 or more minutes. This has proven to be an inefficient and often troublesome procedure minimizing the productivity of the shrink wrap packaging system, wasting time and materials and providing poor packaging results if not completed accurately and correctly.
Therefore, a need exists in the shrink wrap packaging industry for a packaging system which can readily accommodate a wide variety of product configurations, heights and widths without the above-described problems associated with known shrink wrap packaging systems, set up operations and procedures.